I thought that the number of those who already know locate function's signature are fewer than those who don't know. Probably, those who don't know
the signature will read Tajo's guide or guess that locate function may be similar to other SQL string functions. So, I decided that redefine is better.
In addition, Tajo also provides hive mode. It also would be helpful for some guys who want to use both systems at the same time. In hive mode, locate function can be the same to that of Hive.
Anyway, the migration guide that you propose is very nice idea, and the guide would be very helpful for Hive users who want to start Tajo. Actually, I don't know what is efficient way, but I can suggest some important points:
- Tajo supports ANSI SQL.
- Almost users who use Hive already know SQL well.
- So, the guide needs to focus on non-SQL parts, such as File Format.
- For example, how to specify a file format of a table, or how to specify compression specification of a table.
- Non-standard function map between HQL and Tajo SQL will be helpful for that.
If you want to begin to write the migration guide, it would be great to make a separate jira issue.